def test_solve():
with open("files/10.txt") as f:
ct = base64.b64decode(f.read())
with open("files/play_that_funky_music.txt") as f:
pt = f.read()
k, iv = b"YELLOW SUBMARINE", bytes(16)
assert util.AesCbcCipher(k, iv).decrypt(ct).decode() == pt
def encrypt(pt):
pt = junk() + pt + junk()
k, iv = util.rbytes(16), util.rbytes(16)
if util.rbool():
return "ECB", util.AesEcbCipher(k).encrypt(pt)
else:
return "CBC", util.AesCbcCipher(k, iv).encrypt(pt)
def is_padding_ok(self, token):
iv, ct = token[:16], token[16:]
try:
_ = util.AesCbcCipher(self.key, iv).decrypt(ct)
except ValueError:
return False
else:
return True
def test_aes_cbc_cipher():
for n in range(1, 33):
k, iv, pt = util.rbytes(16), util.rbytes(16), util.rbytes(n)
cipher = util.AesCbcCipher(k, iv)
assert cipher.decrypt(cipher.encrypt(pt)) == pt
def __init__(self):
self.key = util.rbytes(16)
self.cbc = util.AesCbcCipher(self.key, self.key)
def create_token(self):
iv, pt = util.rbytes(16), util.rchoice(self.secrets)
return iv + util.AesCbcCipher(self.key, iv).encrypt(pt)
def create_token(self, userdata: str) -> bytes:
if ";" in userdata or "=" in userdata:
raise ValueError("invalid userdata")
s = f"comment1=cooking%20MCs;userdata={userdata};comment2=%20like%20a%20pound%20of%20bacon"
iv = util.rbytes(16)
return iv + util.AesCbcCipher(self.key, iv).encrypt(s.encode())
def is_admin(self, token: bytes):
iv, ct = token[:16], token[16:]
return b";admin=true;" in util.AesCbcCipher(self.key, iv).decrypt(ct)